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2024 Greenhouse Growers Buyers Guide

Based on our experience over the past 5 years and lots of customer feedback, we have compiled a guide below for helping you decide which of our greenhouse kits is right for you. We offer a ranges of styles of polycarbonate greenhouses that are typically small enough not to require a building permit.  For example, generally anything under 100 to 160 square feet such as an 8 foot wide x 12 foot long greenhouse will not require a permit.

Larger high tunnel greenhouses may be subject to different requirements, but are typically permitted on agricultural land. If you are looking at a large 20 wide by 60 foot long high tunnel greenhouse on land designated as agricultural, then likely not. However if you are pouring a concrete foundation and have more permanent roofing than just steel tubes with a poly covering, then yes it may need a permit.

Deluxe Garden Chalet Greenhouse or Sunroom
Get a jump on growing season this Spring with our most popular premium 8 x 12 polycarbonate DIY kit greenhouse made of durable twin-walled polycarbonate.  This kit comes with self-opening vents and a side vent to prevent overheating in hot summer months.  This 8x12 size is under 100 square feet, and won't require a building permit. It has 10 mm thick roof/walls can handle up to 3 feet of snow and provide an R2 value for insulating your starters and veggies on cool Spring or Fall nights.   It is also a super fun project to assemble with your family or kids at home. There are no special tools or experience required other than an electric drill or screwdriver. 
Premium 8x12 Polycarbonate Greenhouse Hothouse by Grizzly Shelter Ltd.

However, there are many factors to consider when buying a greenhouse, such as snow loads in your area, wind and sun exposure as well as proper ventilation. These factors can determine if you will need a clear or glazed single polycarbonate panel, or a light diffusing twin wall panel with more insulating properties.

Did you know that the insulation value of a 2 layer inflated 6 mm poly greenhouse cover has roughly the same R2 value (measure of heat retention) as a 10 mm thick polycarbonate greenhouse?

Mythos Polycarbonate Greenhouse

For example, for high snow areas, we may suggest at least a 6 mm to 10 mm thick twin wall polycarbonate panel for the roof at least, and even walls, or a double-walled 6 mil poly insulated high tunnel greenhouse.  If you are growing fruit trees, you may need more height in your greenhouse so a gothic peak high tunnel greenhouse would make more sense than a wider round one.  Are you looking at 3 season growing to extend your season, or year-round? You may also wish to review our article on greenhouse foundation options as well as permitting for your greenhouse.

TIP: Generally a hobby size polycarbonate greenhouse under 8 feet wide by 12 feet long or under 100 to 160 square feet will not require a permit.

First you need to consider which of the two main categories of greenhouses you need. For typical backyard growing for your family, we suggest a polycarbonate and aluminum frame greenhouse like our best selling Premium 10 YearArch GothicGrand Gardener or Prestige greenhouses.  For larger farms or commercial needs, you will want to considering looking at custom made high tunnel cold frame greenhouses.

Titanium Pruning Gardening Shears

We also sell ground coverings, exterior 6 mil poly rolls and anti-condensation 5 mil poly for preventing mildew inside your greenhouse. We also sell 10 mil thick insulated bubble greenhouse wrap with a 10 year warranty like below. This provides 83% of light through with 95% heat retention and an R2 value at the same time.

Popular Greenhouse Accessories

Here is a list of our most popular accessories for greenhouses. Note that some greenhouses like our premium model may include self opening vents and plant hangers or other accessories:

NEW for 2024: Deluxe 13x15 Garden Greenhouse or Chalet Sunroom

Need more height for growing?  This deluxe greenhouse has 9 foot high side walls and vaulted ceilings give you over 200 square feet of growing room. Click here or the image below to visit the listing.

Deluxe Greenhouse or Sunroom 13x15 Backyard Oasis

We even sell mini apartment sized greenhouse options like the Plant Inn. We also have lean to or pent greenhouses that attach to the side of your house.  And then there's indoor hydroponic growing with LED lighting which have become all the rage with rising costs of lettuce and greens.

HOT TIP: Get Started Growing Early Indoors

 Hydroponic Indoor Growing Kit Grow indoors with this hydroponic LED growing kit that includes Basil, Curly Parsley, Dill, Thyme, Thai Basil and Mint.  6 plants grow at a time, up to 12" tall with this indoor garden. Grows in water so no soil or mess, made simple. Control panel tells you when to add water, reminds you when to add plant food (included), automatically turns lights on and off for your hydroponics growing system


Hobby vs Commercial Greenhouses
Hobby greenhouses are typically at most 6 or 8 feet wide by up to 20 to 24 feet long on average.  Our greenhouses typically have a base 6x8 or 8x8 kit, and offer 4 foot extensions for length. Door heights also range from 70 inches to 74 inches and peak heights from 80 inches to 110. These greenhouses can be used year-round as 4 season shelters for your veggies and plants. These are made from aluminum or hardened resin frames with near unbreakable polycarbonate panels ranging in thickness from 1 mm clear to 10 mm for diffused light, and typically 2 feet wide. The polycarbonate we supply is essentially nearly unbreakable with 5 to 12 year warranties depending on the thickness. The twin-wall polycarbonate sheets are produced based on an Isreali military patent for bullet-proof glass and bank vault kiosks.

To install a hobby size greenhouse, you need to consider how to maximize sun exposure for the kind of plants or veggies you are planning to grow.  You will need to clear a patch of level ground and consider drainage and irrigation as well as what kind of foundation you will need. You may choose to add paving stones or pathways, a slab of concrete or even just embed some pressure treated 4x4s in the ground where that the frame sits upon. 

Garden Greenhouse - Polycarbonate

We can generally deliver greenhouses like the Garden Chalet 10x12 polycarbonate greenhouse pictured here in usually a week or two so from our Mississauga warehouse to anywhere in Canada. 

NEW: Check  our our 13 x 15 Solarium / Greenhouse.

During Spring peak season, however, lead times are longer and you may see some out of stock or backordered items like the Bella, Glory, Prestige or the Plant Inn Mini greenhouses.  We also provide some 3 season (meaning they are not suited to stay up during winter months) hoop-house style 12 wide x 20 to 24 foot long fabric greenhouses from our Calgary AB or Longueuil PQ warehouses which are ready to go kits. Note that all of these best sellers move fast during the Spring growing season and most popular models tend to often sell out by April or May.


If you want to feed multiple families or have larger growing needs, then you should consider our steel tube cold-frame greenhouses (cold-frame means that they don't require heating, but this depends on your region).  They can be as wide as 38 feet and as long as 100 feet and come in round or arch/gothic shapes. You will receive a few boxes of tubes (very by diameter based on width of greenhouse by 1 5/8" to 2 3/8").  You will also receive brackets and purlins (cross braces of steel that keep the ribs 4 feet apart) to attach the greenhouse arches/ribs together.   Note that these custom high tunnel greenhouse kits are custom assembled based on the dimension you require and take 3 to 4 weeks plus shipping on average to arrive depending on your location.

High Tunnel Coldframe Hoop House Greenhouse

You may choose to get a patented Luminate light diffused cover included with C-channel and wiggle wire to attach it to the frame (C-channel allows for customization of side vents). Often starter plants or veggies need a clear poly with more light, and mature crops benefit from a diffused fabric cover for better heat and moisture retention / insulation and less temperature swings. You may also prefer a single layer of 6 mil UV exterior plastic or add a second layer of anti-condensation 6 mil plastic if you choose for an inflated year-round  high tunnel greenhouse.

High Tunnel Cold Frame Greenhouse Grizzly Shelter

Note that the clear light poly (6 mil UV or Interior Anti-condensation poly) is ideal for growing starters, and the Luminate diffused light fabric 5 oz cover is best for added insulation but less light for mature plants.  The diffused fabric cover insulates better and reduces extreme temperate swings, and uses less water.  The clear 6 mil poly adds heat quickly and boosts photosynthesis in early growing plants and veggies.

Note that since these greenhouse high tunnel steel frames are custom made in the US, and then shipped to you directly and take 3 to 4 weeks average for production plus delivery in Canada. To add year-round insulation, you may want to consider a double layer of our 6 mil poly covering with an inside layer of our Thermax anticondensation poly. Note, you would have to typically install a inline duct fan to keep it inflated.  We also offer C-channel and wiggle wire for allowing easy removable of plastic without tear for side vents and more.

Hobby Greenhouse DIY Kits
Our best selling greenhouses in terms of volume are our line of Palram / Canopia hobby polycarbonate greenhouses.  This is a 50 Year old Israeli company that essentially invented bullet-proof glass for the military, and holds patents for near-bullet proof polycarbonate. They are the #1 manufacturer of hobby greenhouses in Canada and we are proud to be authorized dealers for them. They also provide lots of popular accessories, such as temperature sensitive roof vent openers, side louvre vents, irrigation and trellis kits, shade cloth, steel benches, shelves and more.  When you add your greenhouse to your cart, you will be presented with many accessory options to choose from. Some models like the Glory Greenhouse and the Prestige Greenhouse include self-opening roof vents and side louvre vents for example, and others like the Bella greenhouse do not.

What Thickness of Panels Do I Need?
Clear panels are often thinner (1 to 4 mm) and let more light through but don't do well in windy locations.  Thicker panels from 6 to 10 mm thick are twin-walled and diffuse light to prevent "plant burn" and overheating. This thickness level is also much better in terms of snow and wind load ratings. Twin walled thicker panels also add R-value insulation to your greenhouse if you choose to heat it over the winter. A 10 mm thick wall greenhouse will have an R-value of around 2, and a 4 mm will be around R1.

Our hobby size polycarbonate greenhouses are designed to be used 4 seasons a year and withstand winter snow and ice. Read on below for more on snow loads and wind ratings and warranties to be sure you get the right one for your area. Generally polycarbonate which is 6 mm and thicker will withstand a good amount of snow year-round. Know also that 1 mm thick panels will let the most light in, but are not suitable for very windy areas and are typically found on the sides of our polycarbonate greenhouses in some select models.

See our assortment of polycarbonate greenhouses below by panel thickness;

 Thickness Model Warranty Snow/Wind
1 mm Harmony (1 mm walls & roof) 5 Year 15 psf / 90 kmh
1 to 4 mm

Hybrid (1 mm walls, 4 mm roof)
Balance (1 mm walls, 4 mm roof)
Garden Chalet (1 mm walls, 4 mm roof)
Americana (1 mm walls, 4 mm roof)

5 Year 15 psf / 90 kmh
4 mm Mythos (4 mm walls/roof)
Essence (4 mm walls/roof)
5 Year 15 psf / 90 kmh
6 mm Arched Gothic (6 mm walls/roof)
Grand Gardener (6 mm walls, 4 mm roof)
EcoGrow (6 mm walls, 4 mm roof)
Prestige (6 mm walls, 4 mm roof, accessories included) 
5 Year
(7 Year EcoGrow & Prestige)
20 psf / 100 kmh
10 mm Oriana (10 mm walls,1 mm roof)
Glory Premium (10 mm walls/roof, accessories included)

10 Year 
25 psf / 120 kmh

How Easy Are They to Assemble?
People often ask how long they take to assemble and how easy is it. Typically a 8x8 greenhouse like the Bella takes 2 people most of a day to a weekend to assemble with basic tools. This includes unboxing, assembling the frame, attaching the doors and vents and high fives. This can vary to it being a weekend project or longer for larger 8x20 greenhouses and does not include leveling a foundation (see further below for more on that).  Yes, there are a lot of parts with the frame, and lots of nuts and bolts to tighten, so it can be detailed and time-consuming work, especially if you are doing this alone.  It's a great family or group activity to knock off this project in a weekend and see the fruits of your labour by Monday! :)

What Kind of Foundation Do I Need?
For hobby size greenhouses, you basically need to prepare a flat, level foundation to set your greenhouse on.  Most people like a floor of soil, dirt, gravel, or permeable paving stones. Using pressure treated wood 4x4s or 6x6s, a concrete slab or paving stones is best to keep it level.  You may want to make only a wood or stone/cement perimeter to sit the frame on top of, and have a floor of soil for your crops. 

For example, a foundation perimeter of 4x4 pressure treated wood embedded an inch or two into the ground is common, with dirt/soil in the middle and anchored to the ground with rebar, ground earth anchors. For high wind areas, we recommend our greenhouse anchoring kit.  Remember, you need a flat foundation otherwise your greenhouse can "rack" and the door will not close! Each kit includes lag bolts to secure the frame to your foundation.  You can also substitute wood screws to attach the frame to your pressure treated lumber base. For very high wind areas, we also have anchor kits that strap over top of your greenhouse.

Commercial High Tunnel Greenhouses
Commercial hoop houses, high tunnel or cold-frame greenhouses (the same thing) can be up to 38 feet wide and 15'3" high (round) or 34 feet wide and 12' high for arched or gothic shapes.  They include 30 inch anchor tubes that you drive ideally 20 inches into the ground, and then slide rib tubes into them.  Brackets attach cross braces (purlins) to ensure the ribs stay upright and are solid. End panels come "framed" for optional door and vent openings. Vents can be provided as accessories.  Our high tunnel steel greenhouse frames are made with US steel, and shipped to all provinces in Canada except northern territories.

Click here for more high tunnel product information and brochures.

Please contact us at 1 833 GET GRIZ or via email here with any questions.